A semiconductor module having so-called 2-in-1 structure is proposed in, for example, Patent Literature 1 as a semiconductor module forming an inverter. The proposed semiconductor module includes a semiconductor chip having a switching element forming an upper arm and another semiconductor chip having a switching element forming a lower arm. The switching elements of the respective semiconductor chips are connected in series. In the proposed semiconductor module, the respective semiconductor chips have a common configuration and each is provided with an IGBT element.
In each semiconductor chip provided with the IGBT element, an upper heat sink is disposed on an emitter side and a lower heat sink is disposed on a collector side. The switching element of the upper arm and the switching element of the lower arm are electrically connected by connecting the upper heat sink on the upper arm side and the lower heat sink on the lower arm side. The lower heat sink on the upper arm side is connected to a first main terminal (positive-electrode terminal), the lower heat sink on the lower arm side is connected to a second main terminal (output terminal), and the upper heat sink on the lower arm side is connected to a third main terminal (negative-electrode terminal). When viewed from above the upper heat sinks, the first through third main terminals are provided to extend in a same direction with respect to the semiconductor chips. When an interval between the first main terminal and the third main terminal becomes wider, parasitic inductance becomes larger. In order to avoid such an inconvenience, the third main terminal is disposed between the first main terminal and the second main terminal.
Each semiconductor chip also has a gate pad and a Kelvin-emitter pad as control pads controlling the IGBT element provided to the semiconductor chip. The former control pad and the latter control pad are electrically connected to a gate terminal and a Kelvin-emitter terminal, respectively.
In the semiconductor module configured as above, a main current from the first main terminal to the second main terminal and a main current from the second main terminal to the third main terminal are switched by alternately switching ON and OFF the respective switching elements of the upper arm and the lower arm.